Surgical cutting and fastening device with descendible second trigger arrangement

ABSTRACT

A nested trigger assembly for a surgical instrument may generally comprise a first trigger and a second trigger, wherein the first trigger and the second trigger are movable together on a first stroke of the nested trigger assembly, wherein the second trigger is configured to be biased away from the first trigger after the first stroke and before a second stroke, and wherein the second trigger is configured to be moved toward to the first trigger during the second stroke. A surgical instrument may generally comprise a shaft comprising a proximal end and a distal end, a handle extending from the proximal end, wherein the handle comprises a gripping portion, and a nested trigger assembly extending from the handle. The nested trigger assemble may comprise one of a separable trigger assembly and a divisible trigger assembly.

BACKGROUND

1. Field of the Invention

The present invention generally relates to medical devices and methods,and in particular, surgical instruments configured to weld and/or incisetissue.

2. Description of the Related Art

In various open, endoscopic, and/or laparoscopic surgeries, for example,it may be necessary to coagulate, seal, and/or fuse tissue. One means ofsealing tissue relies upon the application of electrical energy totissue captured within an end effector of a surgical instrument in orderto cause thermal effects within the tissue. Various mono-polar andbi-polar radio frequency (Rf) surgical instruments and surgicaltechniques have been developed for such purposes. In general, thedelivery of Rf energy to the captured tissue elevates the temperature ofthe tissue and, as a result, the energy can at least partially denatureproteins within the tissue. Such proteins, such as collagen, forexample, may be denatured into a proteinaceous amalgam that intermixesand fuses, or “welds”, together as the proteins renature. As the treatedregion heals over time, this biological “weld” may be reabsorbed by thebody's wound healing process.

In certain arrangements of a bi-polar radiofrequency surgicalinstrument, the surgical instrument can comprise opposing first andsecond jaws, wherein the face of each jaw can comprise an electrode. Inuse, the tissue can be captured between the jaw faces such thatelectrical current can flow between the electrodes in the opposing jawsand through the tissue positioned therebetween. Such instruments mayhave to seal or “weld” many types of tissues, such as anatomicstructures having walls with irregular or thick fibrous content, bundlesof disparate anatomic structures, substantially thick anatomicstructures, and/or tissues with thick fascia layers such as largediameter blood vessels, for example. With particular regard to sealinglarge diameter blood vessels, for example, such applications may requirea high strength tissue weld immediately post-treatment.

The foregoing discussion is intended only to illustrate various aspectsof the related art in the field of the invention at the time, and shouldnot be taken as a disavowal of claim scope.

SUMMARY

In various embodiments, a surgical instrument may generally comprise ashaft comprising a proximal end and a distal end, a handle extendingfrom the proximal end, wherein the handle comprises a gripping portion,and a divisible trigger assembly extending from the handle, wherein aportion of the divisible trigger assembly is movable relative to thegripping portion between an unactuated position, a first actuatedposition, a second actuated position, and a third actuated position. Thedivisible trigger assembly may generally comprise a first triggerportion and a second trigger portion, wherein the first trigger portionand the second trigger portion form a single component when the portionof the divisible trigger assembly is in the unactuated position, whereinthe second trigger portion is released from the first trigger portionwhen the portion of the divisible trigger assembly is in the firstactuated position, wherein the second trigger portion is spaced distallyfrom the first trigger portion when the portion of the divisible triggerassembly is in the second actuated position, and wherein the secondtrigger portion and the first trigger portion again form the singlecomponent when the portion of the divisible trigger assembly is in thethird actuated position.

In various embodiments, a separable trigger assembly for a surgicalinstrument may generally comprise a first trigger and a second trigger,wherein the first trigger and the second trigger are movable together ona first stroke of the separable trigger assembly, wherein the secondtrigger is configured to be biased away from the first trigger after thefirst stroke and before a second stroke, and wherein the second triggeris configured to be moved toward to the first trigger during the secondstroke.

In various embodiments, a surgical instrument may generally comprise ashaft comprising a proximal end and a distal end, a handle extendingfrom the proximal end, wherein the handle comprises a gripping portion,and a separable trigger assembly extending from the handle. Theseparable trigger assembly may generally comprise a first triggermovable between a first position distal from the gripping portion and asecond position proximal to the gripping portion and a second trigger,wherein the second trigger forms part of the first trigger when thefirst trigger is in the first position, wherein the second trigger isconfigured to release from the first trigger when the first trigger isin the second position, and wherein the second trigger is movable towardthe gripping portion once again after the second trigger has releasedfrom the first trigger.

The foregoing discussion should not be taken as a disavowal of claimscope.

BRIEF DESCRIPTION OF THE FIGURES

Various features of the embodiments described herein are set forth withparticularity in the appended claims. The various embodiments, however,both as to organization and methods of operation, together withadvantages thereof, may be understood in accordance with the followingdescription taken in conjunction with the accompanying drawings asfollows.

FIG. 1 is a perspective view of a surgical device comprising a nestedtrigger assembly according to various embodiments.

FIG. 2A includes an end effector of a surgical device in an openconfiguration according to various embodiments.

FIG. 2B includes the end effector of a surgical device in a closedconfiguration according to various embodiments.

FIGS. 3A-F include a surgical device comprising a nested triggerassembly in various positions according to various embodiments.

FIG. 4A is a cross-sectional view of a surgical device comprising anested trigger assembly in an unactuated position according to variousembodiments.

FIG. 4B is a cross-sectional view of a gear rack of a surgical deviceillustrated in FIG. 4A according to various embodiments.

FIG. 4C is a bottom view of the gear rack of FIG. 4B according tovarious embodiments.

FIG. 5 is a cross-sectional view of the surgical device of FIG. 4Acomprising a nested trigger assembly in a first actuated positionaccording to various embodiments.

FIG. 6 is a cross-sectional view of the surgical device of FIG. 4Acomprising a nested trigger assembly in a second actuated positionaccording to various embodiments.

FIG. 7 is a cross-sectional view of the surgical device of FIG. 4Acomprising a nested trigger assembly in a third actuated positionaccording to various embodiments.

FIGS. 8A and 8B are perspective views of a nested trigger assembly for asurgical instrument according to various embodiments.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate various embodiments of the invention, in one form, and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

Various embodiments are directed to apparatuses, systems, and methodsfor the treatment of tissue. Numerous specific details are set forth toprovide a thorough understanding of the overall structure, function,manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Those of ordinary skill in the art will understand thatthe embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative and do notnecessarily limit the scope of the embodiments, the scope of which isdefined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment”, or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” or “in an embodiment”, or the like,in places throughout the specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of an instrument used to treat a patient. The term“proximal” refers to the portion of the instrument closest to theclinician and the term “distal” refers to the portion located furthestfrom the clinician. It will be further appreciated that for concisenessand clarity, spatial terms such as “vertical,” “horizontal,” “up,” and“down” may be used herein with respect to the illustrated embodiments.However, surgical instruments may be used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

Various embodiments of systems and methods of the invention relate tocreating thermal “welds” or “fusion” within native tissue volumes. Thealternative terms of tissue “welding” and tissue “fusion” may be usedinterchangeably herein to describe thermal treatments of a targetedtissue volume that result in a substantially uniform fused-togethertissue mass, for example, in welding blood vessels that exhibitsubstantial burst strength immediately post-treatment. The strength ofsuch welds is particularly useful for (i) permanently sealing bloodvessels in vessel transection procedures; (ii) welding organ margins inresection procedures; (iii) welding other anatomic ducts whereinpermanent closure is required; and also (iv) for performing vesselanastomosis, vessel closure or other procedures that join togetheranatomic structures or portions thereof. The welding or fusion of tissueas disclosed herein is to be distinguished from “coagulation”,“hemostasis” and other similar descriptive terms that generally relateto the collapse and occlusion of blood flow within small blood vesselsor vascularized tissue. For example, any surface application of thermalenergy can cause coagulation or hemostasis—but does not fall into thecategory of “welding” as the term is used herein. Such surfacecoagulation does not create a weld that provides any substantialstrength in the treated tissue.

At the molecular level, the phenomena of truly “welding” tissue asdisclosed herein may result from the thermally-induced denaturation ofcollagen and other protein molecules in a targeted tissue volume tocreate a transient liquid or gel-like proteinaceous amalgam. A selectedenergy density is provided in the targeted tissue to cause hydrothermalbreakdown of intra- and intermolecular hydrogen crosslinks in collagenand other proteins. The denatured amalgam is maintained at a selectedlevel of hydration—without desiccation—for a selected time intervalwhich can be very brief. The targeted tissue volume is maintained undera selected very high level of mechanical compression to insure that theunwound strands of the denatured proteins are in close proximity toallow their intertwining and entanglement. Upon thermal relaxation, theintermixed amalgam results in protein entanglement as re-crosslinking orrenaturation occurs to thereby cause a uniform fused-together mass.

Various embodiments disclosed herein provide electrosurgical jawstructures adapted for transecting captured tissue between the jaws andfor contemporaneously welding the captured tissue margins withcontrolled application of Rf energy. The jaw structures can comprise acutting element which can cut or score tissue independently of thetissue capturing and welding functions of the jaw structures. In variousembodiments, as described in greater detail further below, the jawstructures can comprise first and second opposing jaws that carrypositive temperature coefficient (PTC) bodies for modulating Rf energydelivery to the engaged tissue.

According to certain embodiments, as described in greater detail below,a nested trigger assembly for a surgical instrument may generallycomprise one of a separable trigger assembly and a divisible triggerassembly. A nested trigger assembly may comprise a first trigger and asecond trigger wherein the second trigger may form a portion of thefirst trigger prior to a first stroke of the nested trigger assembly.The first trigger and the second trigger may be movable together on afirst stroke of the nested trigger assembly. The second trigger may beconfigured to be biased away from the first trigger after the firststroke and before a second stroke. In at least one such embodiment, thesecond trigger may be configured to release from the first trigger afterthe first stroke. Thereafter, the second trigger can be movable througha second stroke independently of the first trigger. During and/or afterthe second stroke, the second trigger may reform the nested triggerassembly with the first trigger.

In various embodiments, as described in greater detail further below,the surgical instrument may comprise an end-effector extending from thedistal end of the shaft. The end effector may comprise an openable andcloseable jaw assembly, and a knife edge as described herein. Theend-effector may be configured to perform a first function and a secondfunction. The first trigger may be configured to actuate the firstfunction. In various embodiments, the first function may compriseopening and closing the jaw assembly. The first trigger may comprise aclosure trigger configured to open and close the jaw assembly. Thesecond trigger may be configured to actuate the second function. Invarious embodiments, the second function may comprise transecting tissuein the jaw assembly with the knife edge. The second trigger may comprisea firing trigger configured to move the knife edge distally to transectthe tissue between the jaw assembly.

Referring now to an exemplary embodiment, FIG. 1 illustrates a surgicalinstrument 100 comprising a handle 105, a shaft or introducer 106, andan end effector or working end 110. The shaft 106 may comprise anysuitable cross-section, such as, for example, a cylindricalcross-section and/or rectangular cross-section. In at least oneembodiment, the shaft 106 may comprise a tubular sleeve that extendsfrom the handle 105. In at least one such embodiment, a proximal end ofthe shaft 106 may be attached to the handle 105. In various embodiments,the handle 105 may comprise a gripping portion 102 and a nested triggerassembly, or lever arm, 128 extending from the handle 105. In variousembodiments, as shown in FIG. 1, the nested trigger assembly 128 maycomprise a divisible trigger assembly wherein, as described in greaterdetail below, the trigger assembly 128 may comprise a first triggerportion 130 a and a second trigger portion 130 b.

Further to the above, the end effector 110 of the surgical instrument100 may extend from a distal end of the shaft 106. In variousembodiments, the end effector 110 may be configured for clamping,transecting, and/or welding tissue, as described in greater detailfurther below; however, the end effector 110 may be suitable for varioustypes of surgical devices, such as, for example, endocutters, graspers,cutters, staplers, clip appliers, access devices, drug/gene therapydevices, ultrasound devices, RF and/or laser devices. In variousembodiments, further to the above, the end effector 110 may comprise afirst jaw 122 a, a second jaw 122 b, and at least one electrode. In atleast one such embodiment, the first jaw 122 a may be movable relativeto the second jaw 122 b between an open position and a closed position.In use, the at least one electrode may be adapted to be activated toapply electrosurgical energy to weld tissue captured within the endeffector 110 wherein the at least one electrode may be coupled to aradiofrequency (Rf) energy source.

Referring to FIGS. 2A and B, in various embodiments, the end effector110 may comprise at least openable and closeable jaw assembly comprisingstraight, curved, and/or any other suitably configured jaws. In at leastone embodiment, the first jaw 122 a may be pivoted about an axisrelative to the second jaw 122 b to close onto, capture, and/or engagetissue positioned between the jaws 122 a and 122 b. The jaws 122 a and122 b may also apply a compression force or pressure thereto. In variousembodiments, the first jaw 122 a and second jaw 122 b may each comprisea first positive temperature coefficient (PTC) body portion and a secondpositive temperature coefficient (PTC) body portion, respectively.

Further to the above, the end effector 110 may comprise a translatablemember 140 configured to contact first jaw 122 a and pivot it downwardlytoward second jaw 122 b, as shown in FIG. 2B. In various embodiments, asdescribed in greater detail below, the trigger assembly 128 may beconfigured to actuate the translatable member 140. In at least one suchembodiment, each of the jaws 122 a and 122 b may comprise an elongatechannel 142 disposed outwardly along their respective middle portionswherein the translatable member 140 may slide within channels 142 toopen and close the first jaw 122 a and/or the second jaw 122 b. Thedistal end of translatable member 140 may comprise a flanged “I”-beamconfigured to slide within the channels 142 in the jaws 122 a and 122 b.The I-beam may comprise an upper flange, a lower flange, and a center,or intermediate, portion therebetween. In at least one embodiment, theflanges and the center portion may define “c”-shaped channels on theopposite sides of the translatable member 140. The flanges may defineinner cam surfaces for slidably engaging outward-facing surfaces 162 aand 162 b of the jaws 122 a and 122 b, respectively. More particularly,a first inner cam surface may comprise any suitable profile configuredto slidably engage the outer surface 162 a of the first jaw 122 a, and asecond inner cam surface may comprise any suitable profile configured toslidably engage the outer surface 162 b of the second jaw 122 b suchthat, as translatable member 140 is advanced distally, the cam surfacesmay co-operate to cam the first jaw 122 a toward the second jaw 122 b,and configure the end effector 140 in a closed configuration. As seen inFIG. 2B, the jaws 122 a and 122 b may define a gap, or dimension, Dbetween a first electrode 165 a of the first jaw 122 a and a secondelectrode 165 b of the second jaw when they are positioned in a closedconfiguration. In various embodiments, dimension D may equal a distancebetween approximately 0.0005 inches and approximately 0.005 inches, forexample, and, in at least one embodiment, between approximately 0.001inches and approximately 0.002 inches, for example.

In various embodiments, the translatable member 140 may be at leastpartially advanced toward the distal end 111 of the end effector 110 tomove the first jaw 122 a toward the second jaw 122 b. Thereafter, thetranslatable member 140 may be advanced further toward the distal end111 of the end effector 110 to transect the tissue positioned betweenthe jaws 122 a and 122 b. In certain embodiments, the distal, orleading, end of the I-beam portion may comprise a sharp, or knife, edge161 which may be configured to incise the tissue. Before, during, and/orafter the translatable member 140 is advanced through the tissue, anelectrical current may be supplied to the first electrode 165 a and thesecond electrode 165 bs to weld the tissue. In various embodiments, theoperation of the trigger assembly 128, such as, for example, the secondtrigger portion 130 b, may advance the knife edge 161 to the distal endof a slot or channel 142. After the knife edge 161 has been sufficientlyadvanced, the trigger assembly 128 may be released and moved to itsoriginal, or unactuated, position in order to retract the knife edge 161and/or translatable member 140, and allow the first jaw 122 a to moveinto its open position again. In at least one embodiment, the surgicalinstrument may comprise a jaw spring (not shown) configured to bias thefirst jaw 122 a into its open position and/or a trigger spring, such astrigger spring 101, for example, configured to bias the trigger assembly128 into its unactuated position. Various other jaw closing mechanismsand electrosurgical energy-delivery surfaces are described in thefollowing United States patents, the entire disclosures of which areincorporated herein by reference: U.S. Pat. Nos. 7,220,951; 7,189,233;7,186,253; 7,125,409; 7,112,201; 7,087,054; 7,083,619; 7,070,597;7,041,102; 7,011,657; 6,929,644; 6,926,716; 6,905,497; 6,802,843;6,770,072; 6,656,177; 6,533,784; and 6,500,176.

In various embodiments, the surgical instrument 100 may comprise a firstconductor, such as, for example, an insulated wire, that may be operablycoupled with the first electrode 165 a in the first jaw 122 a, and asecond conductor, such as, for example, an insulated wire, that may beoperably coupled with the second electrode 165 b in the second jaw 122b. The first and second conductors may extend through shaft 106 betweenan electrical connector in the handle 105 and the first electrode 165 aand second electrode 165 b in the end effector 110. In use, the firstand second conductors may be operably coupled to an electrical source145 and a controller 150 by electrical leads in the cable 152 for thefirst electrode 165 a and second electrode 165 b to function as pairedbi-polar electrodes with a positive polarity (+) and a negative polarity(−), for example. In at least one embodiment, one of the first electrode165 a and second electrodes 165 b may be operably coupled with apositive (+) voltage terminal of the electrical source 145 and the otherof the first electrode 165 a and second electrode 165 b may beelectrically coupled with the negative voltage (−) terminal of theelectrical source 145. Owing to the opposite polarities of the firstelectrode 165 a and second electrode 165 b, current may flow through thetissue positioned between the first electrode 165 a and second electrode165 b and heat the tissue to a desired temperature. In certainembodiments, the translatable member 140 may act as an electrode when itis electrically coupled to a positive terminal or negative terminal ofthe electrical source 145, and/or any suitable ground.

According to certain embodiments, a surgical instrument may comprise,one, a shaft comprising a proximal end and a distal end and, two, ahandle extending from the proximal end, wherein the handle comprises agripping portion and a separable trigger assembly extending from thegripping portion. In various embodiments, as mentioned further above,the separable trigger assembly may comprise a first trigger and a secondtrigger. In use, the first and second triggers of the trigger assemblymay be movable between a first, unactuated position spaced apart fromthe gripping portion (FIG. 3A) and a second, actuated position adjacentto the gripping portion (FIG. 3B) in order to close the end effector ofthe surgical instrument. As described in greater detail below, althoughthe second trigger may form part of the first trigger during the firstactuation of the trigger assembly, the second trigger may be configuredto release from the first trigger when the trigger assembly is in thesecond, actuated position. In at least one such embodiment, the secondtrigger may be releasably attached to the first trigger such that afterthe separable trigger has been moved into its second position, thesecond trigger can detach from the first trigger and return back to itsunactuated condition (FIG. 3C). Such movement of the second trigger canoccur independently of the first trigger, as illustrated in FIG. 3D.Thereafter, referring now to FIG. 3E, the second trigger may be movabletoward the gripping portion once again to sever the tissue capturedwithin the end effector and/or supply energy to the tissue. In variousembodiments, the second trigger can be reconnected to the first triggerto reform the attached trigger assembly in the third actuation positionof the trigger assembly 128, as illustrated in FIG. 3F, and returned toits unactuated configuration (FIG. 3A).

The operation of divisible trigger assembly 128 described above canallow the surgical instrument to be operated in two separate stages.More particularly, moving the trigger portions 130 a and 130 b of thetrigger assembly 128 between an unactuated position and their firstactuated position can operate the surgical instrument in its first stagewhile moving the second trigger portion 130 b between its secondactuated position and its third actuated position can operate thesurgical instrument in its second stage. Stated another way, in variousembodiments, a first stroke of the trigger portions 130 a and 130 btogether can actuate the first operating stage while a second stroke ofthe second trigger portion 130 b, alone, can actuate the secondoperating stage. In various circumstances, further to the above, thefirst operating stage of the surgical instrument can move the jaws ofthe end effector into a closed configuration while the second operatingstage can advance a cutting member relative to the jaws and/or transmitenergy to the tissue captured between the jaws, for example. With regardto the exemplary embodiment depicted in FIGS. 4A-7, the first operatingstage can advance a cutting member a first, or initial, distance whichcauses the cutting member to contact the jaws of the end effector andmove the jaws into a closed position while the second operating stagecan advance the cutting member a second, or final, distance to thedistal ends of the jaws, for example. Thus, a first stroke of thetrigger assembly 128 can advance the cutting member a first distance toclose the jaws while a second stroke of the second portion 130 b of thetrigger assembly 128 can advance the cutting member a second distance tocut the tissue for example.

As shown in FIGS. 4A-4C, further to the above, the surgical instrument100 may comprise a gear rack 104 which is operably engaged with thetrigger assembly 128 such that the first actuation of the triggerassembly 128 can advance the gear rack 104 a first distance and thesecond actuation of the trigger assembly 128 can advance the gear rack104 a second, or subsequent, distance. In various embodiments, as shownin FIG. 4B, the gear rack 104 may comprise a set of gear teeth 103 a anda set of ratchet teeth 103 b, wherein the trigger assembly 128 canengage the set of gear teeth 103 a during the first actuation of thetrigger assembly 128 and the set of ratchet teeth 103 b during thesecond actuation of the trigger assembly 128. The translatable member140 of the surgical instrument 100 may be coupled, or connected, to thegear rack 104 such that the advancement of the gear rack 104 can betransmitted to the translatable member 140. As described in greaterdetail below, the retraction of the gear rack 104 can also retract thetranslatable member 140. In various alternative embodiments, thetranslatable member 140 may comprise the set of gear teeth 103 a and theset of ratchet teeth 103 b wherein a trigger assembly could directlyengage the translatable member in lieu of engaging the intermediate gearrack 104. In any event, in at least one embodiment, the set of gearteeth 103 a may be offset from the set of ratchet teeth 103 b. As shownin FIG. 4C, the set of gear teeth 103 a may be in a different plane thanthe set of ratchet teeth 103 b.

As shown in FIGS. 4A and 5, the first trigger portion 130 a may compriseone or more drive members, such as gear teeth 107, for example,extending therefrom which are configured to engage the set of gear teeth103 a. During the first actuation of the trigger assembly 128, at leastone gear tooth 107 may be configured to engage one or more of the gearteeth 103 a and drive the rack 104 forward, or distally. Thus, as thefirst trigger portion 130 a and the second portion 130 b of the triggerassembly 128 are both moved toward the gripping portion 102 during thefirst actuation of the trigger assembly 128, as described above, therack 104 and the translatable member 140 can be advanced distally. Asdiscussed above, the translatable member 140 can close the jaws 122 aand 122 b when the first trigger portion 130 a is moved to the firstactuated position. When the trigger assembly 128 has reached its firstactuated position (FIG. 5), the jaws 122 a and 122 b may be in theirfully closed configuration. In various embodiment, one or more or thegear teeth 103 a may prevent the rack 104 from returning to its unfiredposition as long as the first trigger portion 130 a is held in itssecond actuated position against the gripping portion 102. As describedin greater detail below, the first trigger portion 130 a can include alocking mechanism which can be configured to engage the gripping portion102 and releasably hold the first trigger portion 130 a in its secondactuated position.

In various embodiments, referring again to FIG. 5, the second triggerportion 130 b may comprise at least one drive member, such as pawl 108,for example, extending therefrom which is configured to engage the setof ratchet teeth 103 b. The reader will note when comparing FIGS. 4A, 5,and 6 that the set of ratchet teeth 103 b may not be aligned with thepawl 108 prior to the first actuation of the trigger assembly 128. Thus,in various embodiments, the first actuation of the trigger assembly 128,and the corresponding initial distal movement of the rack 104, may berequired in order to operably align the set of ratchet teeth 103 b withthe pawl 108 of the second trigger portion 130 b. Once the ratchet teeth103 b have been aligned with the pawl 108, the second trigger portion130 b can be actuated a second time, as described above, in order toadvance the rack 104, and the translatable member 140 coupled thereto,distally once again. As discussed above, the translatable member 140 caninclude a cutting member which can incise the tissue captured betweenthe jaws 122 a and 122 b of the end effector when the second triggerportion 130 b is moved between its second actuated position and itsthird actuated position. When the second trigger portion 130 b hasreached its third actuated position, the translatable member 140 may bein a fully advanced position. The reader will note that set of gearteeth 103 a are free to be advanced distally relative to the firsttrigger portion 130 a after the first trigger portion 130 a has beenmoved into its first actuated position, as described above.

Among other things, the surgical instrument 100 can be configured to,one, manipulate tissue using the jaws 122 a and 122 b, two, transect thetissue using the knife 161 of translatable member 140 after the tissuehas been compressed between the jaws 122 a and 122 b and, three, sealthe tissue using energy supplied to at least one of the jaws 122 a and122 b as described in greater detail below. In use, in variouscircumstances, a surgeon may desire to manipulate the tissue prior totransecting and/or sealing the tissue. In various embodiments, thesurgical instrument 100 may be suitable for these purposes as the firstactuation of the trigger assembly 128 may only advance the translatablemember 140 a sufficient distance to close the jaws 122 a and 122 bwithout transecting the tissue captured therein and/or without heatingthe tissue. Thus, in the event that the surgeon desired to re-open thejaws 122 a and 122 b and re-position the jaws 122 a and 122 b relativeto the tissue, the surgeon may do so prior to the transection of thetissue and/or prior to the application of energy to the tissue. Incertain embodiments, the surgical instrument 100 can include a lockingmechanism which holds the first trigger 103 a in its first actuatedposition and, thus, holds the jaws 122 a and 122 b in their closedconfiguration. In such embodiments, the surgical instrument 100 canfurther include a release button, such as release button 176, forexample, which can be configured to unlock the first trigger portion 103a and allow the first trigger portion 103 a to be returned to itsunactuated position. Correspondingly, the return of the first triggerportion 103 a to its unactuated position can allow the jaws 122 a and122 b to return to their actuated configuration wherein the jaws 122 aand 122 b can then be repositioned relative to the tissue, as describedabove. In various embodiments, the surgical instrument 100 can furtherinclude at least one return spring, such as trigger spring 101, forexample, configured to return the trigger assembly 128 to its unactuatedposition and at least one spring configured to bias the jaws 122 a and122 b into an open configuration after the trigger assembly 128 has beenreleased from its second actuated position.

As outlined above, the surgical instrument 100 can be configured toapply energy to, or direct electrical current through, the tissuecaptured between the jaws 122 a and 122 b. In various embodiments, thejaws 122 a and 122 b can each include one or more electrodes, orconductive surfaces, which can be electrically coupled to the terminalsof a power source having different voltage potentials. In variousembodiments, the surgical instrument 100 can be configured such that atleast one of the electrodes is electrically disconnected from the powersource prior to and/or during the first actuation of the triggerassembly 128. In at least one such embodiment, the surgical instrument100 may comprise a lockout mechanism which is configured to preventcurrent from flowing from the energy source 145, for example, to atleast one of the electrodes, such as, for example, the first electrode165 a and/or second electrode 165 b, until the trigger assembly 128 isin the second actuated position and/or moving between the secondactuated position and the third actuated position, for example. In atleast one such embodiment, the surgical instrument 100 can include alockout system including a plurality of switches which must be actuatedto close an electrical circuit including the first electrode 165 a, thetissue, the second electrode 165 b, and the energy source 145, forexample, and allow the current to flow through the tissue. In theembodiment in which the circuit is closed only when the second triggerportion 103 b is being moved from its second actuated position to itsthird actuated position, for example, the second actuation of thetrigger assembly 128 controls the application of energy to the tissue.This embodiment is described in greater detail further below, althoughother switch arrangements to control the application of energy to thetissue are contemplated and could be used with the surgical instrumentsdescribed herein.

Referring again to FIG. 4A once again, the reader will note that thesecond trigger portion 103 b of the trigger assembly 128 includes anelectrical contact, or connector bar, 198 mounted thereto. In theunactuated position of the trigger assembly 128, illustrated in FIG. 4A,the connector bar 198 is engaged with a first crescent contact 196mounted to the housing of the surgical instrument handle. In variousembodiments, the surgical instrument handle includes the first crescentcontact 196 and, in addition, a second crescent contact 197 wherein thecrescent contacts 196 and 197 are not in electrical communication withone another except when the connector bar 198 is in contact with both ofthe first crescent contact 196 and the second crescent contact 197. Invarious embodiments, the first crescent contact 196 and/or the secondcrescent contact 197 may each be comprised of a conductive material,such as copper, brass, and/or any other suitable metal, for example. Incertain embodiments, the first crescent contact 196 may have a lengthgreater than or equal a length of the second crescent contact 197 suchthat the connector bar 198 is only in contact with the first crescentcontact 196 and not the second crescent contact 197, for example, whenthe trigger assembly 128 is in certain positions during its stroke.Further to the above, referring to FIG. 4A once again, the connector bar198 is in contact with the first crescent contact 196 but not the secondcrescent contact 197 when the trigger assembly 128 is in its unactuatedposition. In this position, the circuit including the supply conductor189, the first electrode 165 a, the second electrode 165 b, and a returnconductor is in an open condition as current cannot flow between thefirst crescent contact 196 and the second crescent contact 197. Thus,when the trigger assembly 128 is in its unactuated position, currentcannot flow through the tissue captured between the jaws 122 a and 122b. When the trigger assembly 128 is moved toward its first actuatedposition from its unactuated position, as described above, the barconnector 198 can electrically connect the first crescent contact 196and the second crescent contact 197. While in some embodiments theconnection between the contacts 196 and 197 may be sufficient to closethe electrical circuit within the surgical instrument, in otherembodiments, however, other switches may need to be closed beforecurrent can flow through the circuit as described in greater detailfurther below.

When the trigger assembly 128 is moved into its first actuated position,referring now to FIG. 5, the first trigger portion 130 a can contact andclose a first switch 199 a. In at least one such embodiment, the firsttrigger portion 130 a can include a tab 190 a which can contact thefirst switch 199 a. In this first actuated position of the triggerassembly 128, as the reader will recall, the jaws 122 a and 122 b havebeen moved into a closed configuration. In certain embodiments, theclosing of the first switch 199 a could close the electrical circuitwithin the surgical instrument 100 thereby allowing current to flowthrough the tissue captured between the closed jaws 122 a and 122 b. Insuch embodiments, the current can flow through the tissue prior to thesecond stroke of the trigger assembly 128 and prior to the distaladvancement of the translatable member 140. In certain otherembodiments, other switches may need to be closed subsequent to closingfirst switch 190 a in order to close the electrical circuit within thesurgical instrument 100. Referring now to FIG. 6, the first triggerportion 130 a can remain in contact with the first switch 199 a as thesecond trigger portion 130 b is moved into its second actuated position.When the second trigger portion 140 b reaches its second actuatedposition, a tab 190 b extending from the second trigger portion 130 bcan contact and close a second switch 199 b. At this point in theoperation of the surgical instrument, the jaws 122 a and 122 b are in aclosed configuration and the first switch 199 a and the second switch199 b are in a closed state; however, the connector bar 198 is not incontact with both of the first and second crescent contacts 196 and 197and, thus, current cannot flow through the circuit to the end effector.Once the second trigger portion 130 b is advanced from its secondactuated position to its third actuated position as described above, theconnector bar 198 can electrically couple the first crescent contact 196and the second crescent contact 197 and the entire electrical circuitwithin the surgical instrument 100 can be in a closed configurationthereby allowing current to flow through the tissue.

As described above, and referring to FIG. 4A again, the electricalcircuit defined within the surgical instrument 100 can include a supplyconductor 198 that can be electrically coupled with an electrode withinthe first jaw 122 a and/or the second jaw 122 b. As also describedabove, a plurality of switches can be present within the supplyconductor 189 which may need to be closed in order for current to flowthrough the supply conductor 189. Thus, the supply conductor 189 cancomprise a plurality of conductor segments which electrically connectthe switches. For example, the supply conductor 189 can comprise a firstsegment 189 a which electrically couples a cut-off switch 194 with thesupply source discussed above. In use, a surgeon can insert the surgicalinstrument 100 into a patient with the switch 194 in an open conditionand close the switch 194 prior to the operation of the surgicalinstrument 100 described above. Such a cut-off switch can reduce thepossibility of inadvertently supplying energy to the end effector. Inany event, the supply conductor 189 can further comprise a secondsegment 189 b which can electrically couple the cut-off switch 194 andthe first switch 199 a and, in addition, a third segment 189 c which canelectrically couple the first switch 199 a and the first crescentcontact 196. The supply conductor 189 can further comprise a fourthconductor segment 189 d which can electrically couple the secondcrescent contact 197 and the second switch 199 b and, in addition, afifth conductor segment 189 e which can electrically couple the secondswitch 199 b and at least one electrode in the end effector. Thus, whenthe cut-off switch 194, the first switch 199 a, and the second switch199 b are in a closed configuration and the connector bar 198 has closedthe connection between crescent contacts 196 and 197, current can flowto the end effector as described above. In such embodiments, the cut-offswitch 194, the first switch 199 a, the second switch 199 b and thecrescent contacts 196 and 197 can be in series with one another.

Further to the above, the translatable member 140 can be advanceddistally at the same time that energy is being applied to the tissuecaptured within the end effector, i.e., during the second stroke of thetrigger assembly 128. When the second trigger portion 130 b has reachedits third actuated position, as described above, the circuit can remainclosed thereby allowing the surgeon to apply additional energy to thetissue, if so desired. Upon returning the trigger assembly 128 to itsunactuated position, the first switch 199 a may open therebyinterrupting the flow of electrical current through the supply conductor189. Furthermore, once the trigger assembly 128 has been returned to itsunactuated position, the connector bar 198 may no longer connect thefirst crescent contact 196 to the second crescent contact 197 whichwould also interrupt the flow of electrical current through the supplyconductor 189. In certain embodiments, the surgical instrument 100 canfurther comprise a trigger return spring operably coupled with the firsttrigger portion 130 a and/or the second trigger portion 130 b which canbe configured to return the first trigger portion 130 a and/or thesecond trigger portion 130 b to their unactuated positions. In at leastone such embodiment, the surgical instrument 100 can include a firsttrigger spring operably coupled with the first trigger portion 130 a anda second trigger spring operably coupled to the second trigger portion130 b wherein the first and second trigger springs can be configured toreturn the first and second trigger portions 130 a and 130 bindependently of one another and/or at the same time. In variousembodiments, the surgical instrument 100 can comprise at least onebiasing spring, such as spring 109, for example, having a first endmounted to the handle housing and a second end mounted to the gear rack104 which can be configured to pull the gear rack 104 proximally towardits unfired position.

Further to the above, the first and second trigger portions 130 a and130 b can advance the gear rack 104 distally and, as the triggerportions 130 a and 130 b are being returned to their unactuatedpositions, the spring 109 can bias the rack 104 back to its unactuatedposition. In at least one such embodiment, the pawl 108 can sliderelative to the ratchet teeth 103 b and the gear teeth 103 a can remeshand reset relative to the gear teeth 107 extending from the firsttrigger portion 130 a. At such point, the surgical instrument 100 can bereused once again to capture tissue between the jaws 122 a and 122 b,apply energy to the tissue, and/or transect the tissue, as outlinedabove.

As mentioned above, the handle 105 may comprise a locking mechanismconfigured to retain the first trigger portion 130 a in its firstactuated position. For example, the first trigger portion 130 a cancomprise a lock 170 extending therefrom which can comprise a cantileverarm 171 and a latching, or locking surface, 172 which can be configuredto enter a lock cavity 174 defined in the gripping portion 102 when thefirst trigger portion 103 a is moved into its first actuated position.In at least one such embodiment, the locking surface 172 can move behinda lock surface 173 defined in the lock cavity 174. In order to unlockthe first trigger portion 130 a, the surgical instrument 100 can furthercomprise an actuator 176 which can be depressed to push the lock 170 outof the lock cavity 174. More particularly, the actuator 176 can beoperably connected to a lever arm 175 which can be rotated or pivoted tocontact the lock 170 when the actuator 176 is depressed. Once theactuator 176 is released by the surgeon, a return spring 177 canreposition and reset the actuator 176 and the lever arm 175.

In various embodiments, the trigger assembly 128 may comprise a releasemechanism movable between a first position in which it is engaged withthe second trigger portion 130 b and a second position in which it isdisengaged from the second trigger portion 130 b. The release mechanismmay be in the first position when the portion of the trigger assembly128 is in the unactuated position and when the trigger assembly 128 ismoved between its unactuated position and its first actuated position.The release mechanism can be moved from its first position to its secondposition to uncouple the second trigger portion 130 b from the firsttrigger portion 130 a. Thus, in various embodiments, the releasemechanism can hold the first trigger portion 130 a and the secondtrigger portion 130 b together during the first actuation of the triggerassembly and release the second trigger portion 130 b after the firstactuation such that the second trigger portion 130 b can be actuatedonce again as described above.

Referring to FIGS. 8A and 8B, according to certain embodiments, aseparable trigger assembly 228 for a surgical instrument may generallycomprise a first trigger 230 a and a second trigger 230 b. The firsttrigger 230 a and second trigger 230 b may be movable together on afirst stroke of the separable trigger assembly, such as, for example,from an unactuated position to a first actuated position. The secondtrigger 230 b may form a portion of the first trigger 230 a prior to thefirst stroke. The second trigger 230 b may form a portion of the firsttrigger 230 a prior to and during the first stroke. In at least oneembodiment, the second trigger 230 b may be releasably attached to thefirst trigger 230 a after the first stroke. The second trigger 230 b maynot form a portion of the first trigger 230 a after the first stroke.The second trigger 230 b may be configured to be biased away from thefirst trigger 230 a after the first stroke and before a second stroke.The second trigger 230 b may be configured to be moved toward to thefirst trigger 230 a during the second stroke, such as, for example, froma second actuated position to a third actuated position. The secondtrigger 230 b may form a portion of the first trigger 230 a after thesecond stroke.

In various embodiments, the separable trigger assembly 228 may comprisea release mechanism movable between an engaged position in which itcontacts the second trigger 230 b and a disengaged position in which itis free from contact with the second trigger 230 b. The releasemechanism may be in the engaged position prior to and during the firststroke and after the second stroke.

In various embodiments, the surgical instrument may comprise a switchthat may be actuated to supply current to the electrodes positionedwithin the end effector. The surgical instrument may comprise a switchthat may be tripped to supply current to the electrodes positionedwithin the end effector when the trigger assembly is moved into thethird actuated position. In at least one embodiment, the switch may bein an open configuration as the trigger assembly is moved through therange of motion from the unactuated position to the third actuatedposition, and once tripped by the trigger assembly, such as, forexample, when the second trigger is in the third actuated position, theswitch may be in a closed configuration as the trigger assembly is movedthrough from the third actuated position to the unactuated position. Invarious embodiments, current may not flow through the electrodes in theend effector as the trigger assembly is moved from the unactuatedposition to the first actuated position and as the first jaw is beingmoved into its closed position.

In various embodiments, current may flow through the electrodes as thetrigger assembly is moved from the first actuated position to the thirdactuated position. In various embodiments, current may flow through theelectrodes as the trigger assembly is moved from the second actuatedposition to the third actuated position and as the knife edge is beingadvanced distally by the trigger assembly as described above. In variousembodiments, the switch may be positioned within handle such that theswitch is aligned with the trigger assembly when the trigger assembly isin the third actuated position.

Referring to FIG. 1, the surgical instrument 100 comprising anelectrical source 145 and a controller 150, for example, may beconfigured to provide different electrosurgical energy-deliveryoperating modes which, in certain embodiments, may depend on the amount,or degree, of jaw closure. In any event, in various circumstances,further to the above, the degree of jaw closure may be represented bythe degree of actuation of the trigger assembly 128, such as, forexample, the first trigger portion 130 a, toward the gripping portion102 and/or the axial translation of translational member 140. In variouscircumstances, it may be useful to switch between differentelectrosurgical energy-delivery operating modes depending on the volumeof tissue captured within the end effector 110 of the surgicalinstrument 100 and the amount of compression applied to the tissue. Forexample, the surgical instrument 100 may deliver Rf energy in a firstoperating mode to large volumes of the captured tissue in order to causean initial dehydration of the tissue, wherein the surgical instrument100 may thereafter switch, and/or be switched by controller 150, forexample, to a second operating mode which allows for more effectivetissue welding. In various circumstances, this second operating mode mayprovide a greater amount or a lesser amount of energy to the tissueand/or adjust the manner or location in which the energy is beingsupplied to the tissue. Alternatively, when engaging a lesser volume oftissue, for example, the surgical instrument 100 and/or accompanyingsystem may deliver Rf energy in only one operating mode which can bebest suited for tissue welding, for example.

In various embodiments, surgical instrument 100 and/or accompanyingsystem may comprise a control system and/or controller 150 to switch thesurgical instrument 100 from one operating mode to another mode afterthe jaws 122 a and 122 b have been closed a predetermined amount. Invarious embodiments, the switchover may occur at 10%, 20%, 30%, 40%,50%, 60%, 70%, and/or 80% of the jaw closure, for example. In certainembodiments, the surgical instrument 100 may comprise a sensor (notshown) configured to detect the degree to which the jaws 122 a and 122 bhave been closed. In various embodiments, the switching betweenelectrosurgical modes may be triggered by one or more operationalparameters, such as (i) the degree of jaw closure as described above,(ii) the impedance of the engaged tissue, and/or (iii) the rate ofchange of impedance or any combination thereof. Furthermore, thepolarity of the electrodes may be switched more than two times duringthe operation of the surgical instrument. Other operating modes aredisclosed in U.S. patent application Ser. No. 12/050,462, entitledELECTROSURGICAL INSTRUMENT AND METHOD, filed on Mar. 18, 2008, theentire disclosure of which is incorporated by reference herein.

In various embodiments, as described above, current may flow from oneelectrode to another while passing through the tissue captured by theend effector of the surgical instrument. As also described above, thecurrent passing through the tissue may heat the tissue. In variouscircumstances, however, the tissue may become overheated. In order toavoid such overheating, the electrodes of various surgical instrumentsmay comprise materials which may no longer conduct current, or mayconduct at least substantially less current, when the electrodematerials have reached or exceeded a certain temperature. Stated anotherway, in at least one embodiment, the electrical resistance of theelectrode material may increase with the temperature of the materialand, in certain embodiments, the electrical resistance of the materialmay increase significantly when the material has reached or exceeded acertain transition, or switching, temperature. In various circumstances,such materials may be referred to as positive temperature coefficient,or PTC, materials. In at least some such PTC materials, the PTC materialmay be comprised of a first non-conductive material, or substrate, whichhas a high electrical resistance and, in addition, a second, conductivematerial, or particles, having a lower electrical resistanceinterdispersed throughout the substrate material. In at least oneembodiment, the substrate material may comprise polyethylene and/orhigh-density polyethylene (HDPE), for example, and the conductivematerial may comprise carbon particles, for example. In any event, whenthe temperature of the PTC material is below its transition temperature,the conductive material may be present in the non-conductive material ina sufficient volumetric density such that the current may flow throughthe PTC material via the conductive particles. When the temperature ofthe PTC material has exceeded its transition temperature, the substrate,or non-conductive material may have sufficiently expanded and/or changedstates such that the conductive particles are no longer sufficiently incontact with one another in order provide a sufficient path for thecurrent to flow therethrough. Stated another way, the expansion and/orstate change of the substrate material may cause the volumetric densityof the conductive particles to fall below a sufficient volumetricdensity in order for current to be conducted therethrough, or at leastsubstantially conducted therethrough. In various circumstances, as aresult of the above, the PTC material may act as a circuit breaker whichcan prevent, or at least inhibit, additional energy from reaching thetissue being treated, that is, at least until the PTC material hascooled sufficiently and reached a temperature which is below thetransition, or switching, temperature. At such point, the PTC materialcould begin to conduct current again.

Further to the above, describing a material as having a positivetemperature coefficient of resistance (PTC) may mean that the resistanceof the material increases as the temperature of the material increases.Many metal-like materials exhibit electrical conduction that has aslight positive temperature coefficient of resistance. In suchmetal-like materials, the PTC's variable resistance effect may becharacterized by a gradual increase in resistance that is linearlyproportional to temperature, i.e., a linear PTC effect. A “nonlinear”PTC effect may be exhibited by certain types of polymer matrices, orsubstrates, which are doped with conductive particles. These polymer PTCcompositions may comprise a base polymer that undergoes a phase changeor can comprise a glass transition temperature T_(g) such that the PTCcomposition may have a resistance that increases sharply over a narrowtemperature range.

Polymeric PTC material may consist of a crystalline or semi-crystallinepolymer (e.g., polyethylene) that carries a dispersed filler ofconductive particles, such as carbon powder or nickel particles, forexample, therein. In use, a polymeric PTC material may exhibittemperature-induced changes in the base polymer in order to alter theelectrical resistance of the polymer-particle composite. In a lowtemperature state, the crystalline structure of the base polymer maycause dense packing of the conductive particles (i.e., carbon) into itscrystalline boundaries so that the particles may be in close proximityand allow current to flow through the PTC material via these carbon“chains”. When the PTC material is at a low temperature, numerous carbonchains may form the conductive paths through the material. When the PTCmaterial is heated to a selected level, or an over-current causes I²Rheating (Joule heating) within the PTC material, the polymer basematerial may be elevated in temperature until it exceeds a phasetransformation temperature. As the polymer passes through this phasetransformation temperature, the crystalline structure may change to anamorphous state. The amorphous state may cause the conductive particlesto move apart from each other until the carbon chains are disrupted andcan no longer conduct current. Thus, the resistance of the PTC materialincreases sharply. In general, the temperature at which the base polymertransitions to its amorphous state and affects conductivity is calledits switching temperature T_(s). In at least one embodiment, thetransition or switching temperature T_(s) may be approximately 120degrees Celsius, for example. In any event, as long as the base polymerof the PTC material stays above its switching temperature Ts, whetherfrom external heating or from an overcurrent, the high resistance statewill remain. Reversing the phase transformation allows the conductiveparticle chains to reform as the polymer re-crystallizes to therebyrestore multiple current paths, and a low resistance, through the PTCmaterial. Conductive polymer PTC compositions and their use aredisclosed in U.S. Pat. Nos. 4,237,441; 4,304,987; 4,545,926; 4,849,133;4,910,389; 5,106,538; and 5,880,668, the entire disclosures of which areincorporated by reference herein.

The devices disclosed herein may be designed to be disposed of after asingle use, or they may be designed to be used multiple times. In eithercase, however, the device may be reconditioned for reuse after at leastone use. Reconditioning may include a combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicemay be disassembled, and any number of particular pieces or parts of thedevice may be selectively replaced or removed in any combination. Uponcleaning and/or replacement of particular parts, the device may bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Those ofordinary skill in the art will appreciate that the reconditioning of adevice may utilize a variety of different techniques for disassembly,cleaning/replacement, and reassembly. Use of such techniques, and theresulting reconditioned device, are all within the scope of thisapplication.

Preferably, the various embodiments of the devices described herein willbe processed before surgery. First, a new or used instrument is obtainedand if necessary cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK® bag. The container and instrumentare then placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation kills bacteria on the instrument and in the container. Thesterilized instrument can then be stored in the sterile container. Thesealed container keeps the instrument sterile until it is opened in themedical facility. Other sterilization techniques can be done by anynumber of ways known to those skilled in the art including beta or gammaradiation, ethylene oxide, and/or steam.

Although the various embodiments of the devices have been describedherein in connection with certain disclosed embodiments, manymodifications and variations to those embodiments may be implemented.For example, different types of end effectors may be employed. Also,where materials are disclosed for certain components, other materialsmay be used. Furthermore, according to various embodiments, a singlecomponent may be replaced by multiple components, and multiplecomponents may be replaced by a single component, to perform a givenfunction or functions. The foregoing description and following claimsare intended to cover all such modification and variations.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

1. A surgical instrument, comprising: a shaft comprising a proximal endand a distal end; a handle extending from the proximal end, wherein thehandle comprises a gripping portion; and a divisible trigger assemblyextending from the handle, wherein a portion of the divisible triggerassembly is movable relative to the gripping portion between anunactuated position, a first actuated position, a second actuatedposition, and a third actuated position, the divisible trigger assemblycomprising: a first trigger portion; and a second trigger portion,wherein the first trigger portion and the second trigger portion form asingle component when the portion of the divisible trigger assembly isin the unactuated position, wherein the second trigger portion isreleased from the first trigger portion when the portion of thedivisible trigger assembly is in the first actuated position, whereinthe second trigger portion is spaced distally from the first triggerportion when the portion of the divisible trigger assembly is in thesecond actuated position, and wherein the second trigger portion and thefirst trigger portion again form the single component when the portionof the divisible trigger assembly is in the third actuated position. 2.The surgical instrument of claim 1, wherein the second trigger portionis releasably engaged with the first trigger portion when the portion ofthe divisible trigger assembly is in the unactuated position.
 3. Thesurgical instrument of claim 1, wherein the second trigger portion isreleasably engaged with the first trigger portion when the portion ofthe divisible trigger assembly is in the third actuated position.
 4. Thesurgical instrument of claim 1 comprising a release mechanism movablebetween a first position in which it is engaged with the second triggerportion and a second position in which it is disengaged from the secondtrigger portion, wherein the release mechanism is in the first positionwhen the portion of the divisible trigger assembly is in the unactuatedposition.
 5. The surgical instrument of claim 1 comprising a releasemechanism movable between a first position in which it is engaged withthe second trigger portion and a second position in which it isdisengaged from the second trigger portion, wherein the releasemechanism is in the first position when the portion of the divisibletrigger assembly is in the third actuated position.
 6. The surgicalinstrument of claim 1 comprising an end effector extending from thedistal end of the shaft, the end effector comprising: a first jaw; asecond jaw, wherein said first jaw is movable relative to said secondjaw between an open position and a closed position; and at least oneelectrode.
 7. The surgical instrument of claim 6, wherein the at leastone electrode is adapted to be activated to apply electrosurgical energyto weld tissue.
 8. The electro surgical instrument of claim 6, whereinthe at least one electrode is coupled to a radiofrequency (Rf) energysource.
 9. The electrosurgical instrument of claim 6, wherein the firstjaw and second jaw each comprise a first positive temperaturecoefficient (PTC) body portion and a second positive temperaturecoefficient (PTC) body portion, respectively.
 10. The surgicalinstrument of claim 6 comprising a lockout mechanism to prevent currentfrom flowing from the energy source to the at least one electrode unlessthe divisible trigger assembly is in the second actuated position. 11.The surgical instrument of claim 1 comprising an end effector extendingfrom the distal end of the shaft, the end effector comprising: a firstjaw; a second jaw, wherein said first jaw is movable relative to saidsecond jaw between an open position and a closed position; and a knifebar movable between a first position and a second position, wherein saidsecond trigger portion is operably engageable with said knife bar, andwherein said second trigger portion is configured to move said knife barbetween said first position and said second position.
 12. The surgicalinstrument of claim 11, wherein the knife bar is configured to beactivated to transect tissue when the divisible trigger assembly is inthe second actuated position.
 13. A separable trigger assembly for asurgical instrument, the separable trigger assembly comprising: a firsttrigger; and a second trigger, wherein the first trigger and the secondtrigger are movable together on a first stroke of the separable triggerassembly, wherein the second trigger is configured to be biased awayfrom the first trigger after the first stroke and before a secondstroke, and wherein the second trigger is configured to be moved towardto the first trigger during the second stroke.
 14. The separable triggerassembly of claim 13 comprising a release mechanism movable between anengaged position in which it contacts the second trigger and adisengaged position in which it is free from contact with the secondtrigger, wherein the release mechanism is in the engaged position priorto and during the first stroke and after the second stroke.
 15. Theseparable trigger assembly of claim 13, wherein the second trigger formsa portion of the first trigger prior to the first stroke and after thesecond stroke.
 16. The separable trigger assembly of claim 13, whereinthe second trigger forms a portion of the first trigger prior to andduring the first stroke and after the second stroke.
 17. A surgicalinstrument comprising: a shaft comprising a proximal end and a distalend; a handle extending from the proximal end, wherein the handlecomprises a gripping portion; and a separable trigger assembly extendingfrom the handle, the separable trigger assembly comprising: a firsttrigger movable between a first position distal from the grippingportion and a second position proximal to the gripping portion; and asecond trigger, wherein the second trigger forms part of the firsttrigger when the first trigger is in the first position, wherein thesecond trigger is configured to release from the first trigger when thefirst trigger is in the second position, and wherein the second triggeris movable toward the gripping portion once again after the secondtrigger has released from the first trigger.
 18. The surgical instrumentof claim 17, wherein the second trigger is releasably attached to thefirst trigger when the separable trigger is in the first position. 19.The surgical instrument of claim 17 comprising an end-effector extendingfrom the distal end of the shaft, wherein the end-effector is configuredto perform a first function and a second function, wherein the firsttrigger is configured to actuate the first function, and wherein thesecond trigger is configured to actuate the second function.
 20. Thesurgical instrument of claim 17 comprising a release mechanism movablebetween an engaged position in which it contacts the second trigger anda disengaged position in which it is free from contact with the secondtrigger, wherein the release mechanism is in the engaged position whenthe separable trigger assembly is in the first position, and wherein therelease mechanism is in the disengaged position when the second triggeris positioned distal from the first trigger.